Field of the Invention
The present invention relates to methods for joining together objects, and more particularly to brazing methods for joining non-diffusing ceramic objects.
Description of Related Art
The joining of ceramic materials may involve processes which require very high temperatures and very high contact pressures. For example, liquid phase sintering may be used to join ceramic materials together. In this type of manufacture, at least two drawbacks are seen. First, the hot pressing/sintering of a large, complex ceramic piece requires a large physical space within a very specialized process oven. Second, should a portion of the finished piece become damaged, or fail due to wear, there is no repair method available to disassemble the large piece. The specialized fixturing, high temperatures, and inability to disassemble these assemblies invariably leads to very high manufacturing costs.
Other processes may be geared towards strength, and may yield strong bonds between the pieces that, although structurally sufficient, do not hermetically seal the pieces. In some processes, diffusion bonding is used, which may take significant amounts of time, and may also alter the individual pieces such that they form new compounds near the joint. This may render them unfit for certain applications, and unable to be reworked or repaired and rejoined.
Certain ceramics may allow for the joining of the ceramic pieces with hermetic joints at low temperatures. Ceramic materials may be categorized by their diffusability. The diffusability of the ceramic may play a part in whether low temperature brazing will result in hermetic joining.
What is called for is a joining method for joining ceramic pieces at a low temperature and which provides a hermetic seal, and which allows for repairs.